Spray nozzle, and also spray boom provided therewith

ABSTRACT

Spray nozzle for a spray boom to be fixed to a crop protection machine or the like. The spray nozzle is fixed on a supply line for spraying a fluid. The spray nozzle consists of a spray nozzle holder and a spray nozzle head. The passage of the inflow aperture to the outflow channel is regulated by means of an electromagnetic coil. Each spray nozzle holder can be controlled individually in a very accurate manner by means of such an electromagnetic shut-off valve situated in the spray nozzle holder. Connection between electric coil and spray nozzle holder is achieved by means of a connecting piece.

BACKGROUND OF THE INVENTION

The present invention relates to a spray nozzle for spraying liquids.

Such a spray nozzle is generally known in the prior art. It is used on,for example, a spray boom. European Patent Application 0,373,034describes a method for applying a certain pattern to the ground by aseries of electrically operable spray nozzles. Various other controlmeans for controlling the passage of a fluid such as nutrients and cropprotection products are known in the prior art. The simplest design is amanually operated, electrical or pneumatic valve which is fitted in thespray boom. It controls all or a number of spray nozzles. Environmentalconsiderations and the waste involved mean that this is no longer theoptimum solution. For the fact is that after such a valve has been takeninto the switched-off position the downstream spray nozzles can stilldrip. Besides, with this design it is not possible to control the spraynozzles separately, which can be important if a piece of land extends atan angle relative to the direction of movement of the spray boom.

A first proposal for overcoming this problem is to fit a pneumaticpiston-cylinder in the spray nozzle holder. In this case the pistonoperates a diaphragm which in the unexcited state provides for ashut-off in the passage from the supply line to the spray nozzle head inthe spray nozzle holder. This means that it is possible in principle tocontrol each spray nozzle head separately. However, there are at leasttwo disadvantages involved in such a construction. First, the control bymeans of a diaphragm is relatively sluggish, which is of minorimportance if large quantities of fluid have to be sprayed, but if verysmall quantities have to be dispensed for a short period, it does playan important role. Besides, an extremely large number of components isnecessary for separate control. For such separate control will in thefirst instance be on the basis of electrical signals, which electricalsignals have to be converted into pneumatic signals. Moreover, aseparate compressor has to be fitted on the crop protection machine, orhas to be present elsewhere.

SUMMARY OF THE INVENTION

The object of the present invention is to avoid these disadvantages andto provide a spray nozzle which can be driven electrically, but in thecase of which a spray nozzle can also be produced in a simple manner,using existing components as far as possible. In other words, anelectrically operable spray nozzle can be the characterizing part ofclaim 1.

The invention can be achieved by combining existing spray nozzles whichare suitable for hydraulic use with an electric coil, and interposing aconnecting piece. In an advantageous embodiment, said connecting piececan be provided with a pipe section which abuts the outflow aperture ina sealing manner at the position of that common face, and which isconnected to the valve chamber.

In an embodiment in which large quantities of fluid have to bedisplaced, the outflow aperture can comprise a main and auxiliaryoutflow channel. In such a case the electromagnetic valve acts as thecontrol valve, i.e. by operation of this valve a further valve, and inparticular a diaphragm valve, is controlled.

The embodiments described above are embodiments which in the unexcitedstate of the electromagnetic coil provide a shut-off. Of course, it ispossible to design the device the other way round, i.e. in the unexcitedstate the passage to the spray nozzle head is opened.

With the construction described above, it is no longer necessary toincorporate valves in the supply line, and it is also possible tocontrol the spray nozzles individually. Furthermore, the time duringwhich the various spray nozzles are active can be varied over a sprayboom. This can be important if, for example, in the case of a piece ofland to be treated the direction of movement of the spray boom is at anangle relative to the boundary of the piece of land. Another exemplaryapplication is that in which the conditions over the entire area of thepiece of land concerned are not the same, i.e. at certain points fluidhas to be applied and at other points less or no fluid at all has to beapplied. The above can also depend on the crops present in that place,and can be regulated by means of sensors, possibly combined with GPS andD-GPS and a control system fitted specially for the purpose.

With the current techniques it is possible to use extremely low-capacityelectromagnetic coils. A value of 4, 5 or 8 watts has been foundpossible, so that the total power consumption of a spray boom withseveral dozen spray nozzles is relatively low.

The invention also relates to a spray boom provided with the spraynozzles described above.

It is possible to incorporate a return line or continuous recirculationline for fluid in the above spray boom.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in greater detail below with referenceto exemplary embodiments shown in the drawing, in which:

FIG. 1 shows in perspective view a crop protection machine;

FIG. 2 shows a first embodiment of a spray nozzle;

FIG. 3 shows a second embodiment of a spray nozzle; and

FIG. 4 shows a third embodiment of a spray nozzle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a tractor 1 which is provided near the rear side with abearer 2 on which a spray boom 3 is fixed, in the usual manner. The cropprotection machine consists of a container 7 a for fluid, which isconveyed by way of a supply line 7 to various spray nozzles 5, 6. Inthis case spray nozzle 6 is a so-called edge nozzle, i.e. the sprayprofile does not extend beyond the end limit of spray boom 3. Spray boom3 is suspended from a cable 4 or the like. It is not shown in FIG. 1that a return line may be present for conveying fluid from the supplyline 7 back to container 7 a, in order in this way to avoid effects ofair during starting and the like and to improve bringing toconcentration or flushing. Tractor 1 also has a control 9 which isconnected by means of cables (not shown) to the spray nozzles 5 and 6.

FIG. 2 shows a first exemplary embodiment of a spray nozzle. The spraynozzle indicated by 5 is fixed on supply line 7. Said spray nozzleconsists of a spray nozzle holder 8, which is provided with an inlet 10projecting slightly into supply line 7. The seal is achieved by part 11.Spray nozzle head 12 is fixed on holder 8. It should be understood thatany type of spray nozzle head can be used. Moreover, instead of thespray nozzle holder/spray nozzle head described here, it is alsopossible to use a device consisting of a number of spray nozzle headswhich are fitted by means of a revolver-type construction on the spraynozzle holder, so that the correct spray nozzle head can be selecteddepending on the conditions in which spraying has to be carried out andthe fluid which has to be sprayed.

The spray nozzle holder 8 and spray nozzle head 12 are conventional,commercially available components. Spray nozzle holder 8 is providedwith a flange 27 for the accommodation of a connecting piece 13. Spraynozzle holder 8 and connecting piece 13 can be fixed to each other bymeans of a union nut 14. An armature housing 17 is screwed intoconnecting piece 13, over which armature housing a coil 15 is pushed.Coil 15 consists of a winding 16 which is electrically connected tocontrol 9. Inside armature housing 17 is an armature 19 which can moveto and fro. A spring 18 is present, which spring drives said armature tothe left in the unexcited state. Armature 19 is provided with a sealingface 20 at the free end.

Spray nozzle holder 8 is provided with an inflow channel 23, which byway of a number of supply channels 24 fitted in a circle opens out intoa valve chamber 25. From there, a centrally situated outflow aperture 26extends through a pipe section 29, which outflow aperture opens out intooutflow channel 22 which is in communication with spray nozzle head 12.Seal 20 of armature 19 is designed to interact with the valve seat 21.

On excitation of coil 15, armature 17 will move to the right and thefluid can flow unimpeded out of supply line 7 to spray nozzle head 12.If closure is desired, particularly rapid closure of aperture 26 can beobtained by no longer exciting the coil. No subsequent dripping isfound. Coil 15 can have a relatively low power consumption in theexcited state, such as 4, 5 or 8 watts. All kinds of spray patterns canbe achieved by means of the control. In particular, any desired patterncan be achieved near the end of the spray boom by interaction of theedge spray nozzle 6 with the adjacent spray nozzle 5. Furthermore,selective spraying is possible, and the number of components isrelatively small. In particular, owing to the extremely high switchingspeed, spraying per plant is now achievable, i.e. the spray does notfall between two plants.

FIG. 3 shows a variant of the construction shown in FIG. 2. This spraynozzle is indicated in its entirety by 30. The spray nozzle holder isindicated by 8, as in FIG. 2, because it is largely identical.Differences exist only as regards the control section and the connectingpiece 28. This embodiment is designed in such a way that in the normalunexcited state of winding 16 a free passage opening is present betweensupply line 7 and spray nozzle head 12.

This is achieved by the fact that armature 32 is provided with a ring 33which is immovably connected thereto and is under the influence of aspring 31. In the unexcited state, armature 32 will be moved to theleft, as shown in FIG. 3, and valve chamber 34 will be opened, therebyproviding a communication by way of bypass line 35 between inflowchannel 23 and outflow channel 22. In this construction also, use can bemade of existing spray nozzle holders and spray nozzle headsrespectively.

FIG. 4 shows a construction which is suitable in particular fordispensing large quantities of fluid. This spray nozzle is indicated inits entirety by 40 and consists of a spray nozzle holder 39. Arelatively large union nut 41 is fitted on the connecting piece thereof,for the accommodation of connecting piece 36. Apart from coil 16, adiaphragm 45 loaded by a spring 46 is also present, shutting off themain aperture between inflow channel 43 and outflow channel 44. Inflowchannel 43 is connected to a calibrated control channel 47, which by wayof inlet channel 48 and valve chamber 49 is in communication with mainoutflow channel 52 with larger passage. In the manner shown in FIG. 1,an electromagnetic coil is present, consisting of winding 16, spring 18and armature 19. In the unexcited state, auxiliary outflow channel isclosed. This is caused by the fact that spring 18 drives armature 19into the closed position. Owing to the small surface of armature 19which is exposed to the fluid pressure acting in supply line 7, it ispossible with a relatively light spring to ensure closure of the plungereven at higher pressures. Diaphragm 45 is kept closed by the combinedaction of the fluid pressure and spring 46. If excitation is thenprovided, fluid will move through the auxiliary flow channel to spraynozzle head 12. Owing to the fact that the aperture of the calibratedcontrol channel 47 is smaller than the aperture of the auxiliary outflowchannel 52, fluid will be discharged at a more rapid rate than its rateof inflow. This causes the pressure at the right-hand side of thediaphragm 45 to drop, and the diaphragm can open against the action ofspring 46. The surface exposed to the pressure in the supply lineconsequently increases further, and the valve will remain opened so longas armature 19 makes discharge of fluid possible, with the result thatspray nozzle head 12 will spray the medium.

It is, of course, clear that the construction shown in FIG. 3, which inthe unexcited state is opened, can also be used for the constructionshown with reference to FIG. 4.

Although the invention is described above with reference to a preferredembodiment, it will be understood that numerous variants thereof arepossible without going beyond the scope of the present application.

As indicated above, it is possible to achieve an embodiment of the spraynozzle holder which is particularly suitable for electromagneticoperation, in which case then new moulds for the injection moulding workare necessary.

These and other proposals are considered to lie within the scope of theappended claims.

What is claimed is:
 1. A spray nozzle for spraying fluids, the spray nozzle being provided with electrical operating means, said spray nozzle comprising, a spray nozzle head, and a spray nozzle holder provided with an inflow aperture and an outflow aperture, which open out in a common face, and a flange having a circumferential screwthread; said electrical operating means comprising a coil, with an armature which is movable in a linear manner, one end of said armature being connected to a valve body fitted in a valve chamber, in which a connecting piece is present, placed between said spray nozzle holder and said coil at said common face, said connecting piece comprising separate inflow and outflow channels and being provided with a union nut to cooperate with said circumferential screwthread, and in which said valve chamber is provided in at least one of said connecting piece and said electrical operating means.
 2. The spray nozzle according to claim 1, in which said connecting piece is provided with a pipe section which abuts the outflow aperture in a sealing manner at the position of said common face, and which is connected to said valve chamber.
 3. The spray nozzle according to claim 1, in which the outflow aperture comprises main and auxiliary outflow channels.
 4. The spray nozzle according to claim 1, in which said electrical operating means in the excited state consume less than 10 W.
 5. A spray boom fixed to a crop protection machine or the like, comprising at least one supply line for the fluid stored in a container to be sprayed, and also a number of spray nozzles fitted on the supply line, wherein each spray nozzle is provided with electrical operating means, each said spray nozzle comprising, a spray nozzle head, and a spray nozzle holder provided with an inflow aperture and an outflow aperture, which open out in a common face, and a flange having a circumferential screwthread; said electrical operating means comprising a coil, with an armature which is movable in a linear manner, one end of said armature being connected to a valve body fitted in a valve chamber, in which a connecting piece is present, placed between said spray nozzle holder and said coil at said common face, said connecting piece comprising separate inflow and outflow channels and being provided with a union nut to cooperate with said circumferential screwthread, and in which said valve chamber is provided in at least one of said connecting piece and said electrical operating means. 